Dimensioning in Technical Drawings: A Comprehensive Guide
Standardization of Dimensioning
Index
1. Application of Bounds: General Rules of Dimensioning
2. Terms of Bounding
3. Elements of the Quotation
4. Types of Dimensioning
5. Types of Arrows. Symbols Preceding the Number of Bound
6. Method of Bounding
– Limiting of Edges
– Limiting of Diameters
– Limiting of Radii
7. Special Indications: Bounding of Arcs, Strings, and Angles
General Rules of Dimensioning
· Appear the dimensions necessary for the part to be defined.
· The dimensions must not be repeated, post the required minimum.
· All dimensions are placed in the view that better defines the magnitude bounded.
· All dimensions are expressed in the same unit.
· Elevation figures should be placed so that they can read in the normal position of the drawing or watching it from the right.
· Elevation figures remain above the dimension line and in the same direction.
Terms of Bounding
Functional Cota: Cota has importance in the role or roles assigned to a piece
Nonfunctional Cota: Cota is not essential for the function of a piece
Assistant Cota: Cota given only for information and whose value can be derived from other dimensions of the plane
What is an Item? One element is an individual characteristic of the piece as a flat surface, a cylindrical surface, two parallel surfaces, a corner…
Limiting of Edges
“The dimension lines can not coincide with the edges…
-… or may coincide with the axes
-… or be below them…
He plotted perpendicular to the line to narrow or in some cases oblique always remain parallel to each other.
“The lines of symmetry can be used as auxiliary dimension lines.
“The chamfers or rounded pieces is bounded between the points of intersection of the” extensions of the edges.
-Reference lines and dimension should not be cut.
“The dimension lines do not intersect each other or with any other line.
“The dimension lines are placed in series in line.
“The dimension lines do not intersect each other or with any other line.
-To avoid the parallel marking the dimensions will post more remote and nearer the lower figure.
“If the arrows are close together are taken out of the auxiliary lines
“If the arrows can not be taken out and replaced with a point…
“If the figure has little room dimension shall be placed outside, on the right
-… and figures will be drawn with a reference line while maintaining its direction.
Limiting of Diameters
The arches over 180º will be identified with its diameter.
The dimension line can not coincide with the axis of symmetry.
Dimension lines are placed at different angles.
The arches over 180º will be identified with its diameter.
The dimension line can not coincide with the axis of symmetry.
Dimension lines are placed at different angles.
No further restrict two concentric circles. The rest will be identified in another view.
Symbol is added to the diameter when it is not clear that we are annotating a circle.
Limiting of Radii
The arcs less than or equal to 180º will be identified with its radius.
The arrow and the number of chain out if there will little room.
If you do not know the center of the arch placed before the figure the symbol dimension of radius R.
The line will carry the same direction as if it were a radio.
Additional information: Arcs, Strings, and Angles
To narrow the strings above the dimension line gets the length of the string
To narrow the arc, place a dimension line as the image showing the arc length
At narrow angles puts the same dimension line that arcs and sets covering many degrees the angle
TYPES OF BOUNDARIES
“In series
“By overlapping levels
“In parallel
BOUNDARIES BY COORDINATES
-TO TABLE:
Coordinates are placed in a table
TABLE-SIN:
Coordinates are placed next to each item
Types of Arrows
Symbols Preceding the Number of Bound
Symbols Preceding the Number of Bound
Enrollment figures bound
There are two methods of registration of dimensions:
METHOD 1
The benchmark figures are placed parallel to their dimension lines, centered, above and slightly separated from them. Should be read from below or from the right.
METHOD 2
The figures must register to be read from below. The non-horizontal dimension lines are cut in half to bring the figure.
Formative test
1. Son those essential dimensions, so the piece can fulfill their function:
Functional Cota
2. Líneas parallel to the surface of the measurement object
Dimension lines
3. Boundedness What rule is not complied with?
Dimension lines should not cross
Define what is quotation:
The annotation is the process of recording, with lines, numbers, signs and symbols, through an object on a preliminary drawing of it, following a series of rules and conventions established by rules.
Plot the components involved in an aside
The basic elements involved in the stage directions are:
Dimension lines: These are lines parallel to the surface of the measurement object.
Figures dimension: It is a number that indicates the magnitude. It puts focus on the dimension line. May be in the middle of the dimension line, breaking it, or about the same, but in the same drawing will follow a single criterion.
Symbol final dimension: The dimension lines will be completed at their ends by a symbol. In mechanical drawing using the arrow.
Lines auxiliary or reference dimension: They start drawing lines perpendicular to the surface to narrow and limit the length of the dimension lines. Should protrude slightly from the dimension lines.
Symbols: Sometimes the figure of elevation is accompanied by a symbol indicative of formal characteristics of the piece, which simplify their marking, and sometimes can reduce the number of views needed to define the piece. The most common symbols are: